Initial scaffold — NASBackup iOS app

Full project scaffold: XcodeGen project.yml, Core models/protocols/errors,
SMBService (kishikawakatsumi/SMBClient), SFTPService (Citadel 0.9.2),
PhotoLibraryService, LANMonitor, BackupEngine, BackgroundTaskManager,
all feature UIs (Login, Connect, Browse, Backup, History, Settings),
Shared components and theme. Builds clean with zero errors.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Shared/Theme/AppTheme.swift

@@ -0,0 +1,48 @@
+import SwiftUI
+
+enum AppTheme {
+    // Brand
+    static let blue = Color(hex: "#2563EB")
+    static let blueLight = Color(hex: "#3B82F6")
+    static let green = Color(hex: "#16A34A")
+    static let greenLight = Color(hex: "#22C55E")
+    static let red = Color(hex: "#DC2626")
+    static let orange = Color(hex: "#EA580C")
+
+    // Backgrounds
+    static let background = Color.white
+    static let cardBackground = Color.white
+    static let cardBorder = Color(hex: "#E5E7EB")
+
+    // Text
+    static let textPrimary = Color(hex: "#111827")
+    static let textSecondary = Color(hex: "#6B7280")
+    static let textTertiary = Color(hex: "#9CA3AF")
+
+    // Status
+    static let connectedBorder = Color(hex: "#16A34A")
+    static let lanBorder = Color(hex: "#2563EB")
+
+    // Typography
+    static let titleFont = Font.system(size: 28, weight: .bold, design: .default)
+    static let headlineFont = Font.system(size: 17, weight: .semibold)
+    static let bodyFont = Font.system(size: 15, weight: .regular)
+    static let captionFont = Font.system(size: 13, weight: .regular)
+    static let smallFont = Font.system(size: 11, weight: .medium)
+
+    static let cardCornerRadius: CGFloat = 12
+    static let cardPadding: CGFloat = 16
+    static let sectionSpacing: CGFloat = 24
+}
+
+extension Color {
+    init(hex: String) {
+        var h = hex.trimmingCharacters(in: .init(charactersIn: "#"))
+        if h.count == 3 { h = h.map { "\($0)\($0)" }.joined() }
+        let n = UInt64(h, radix: 16) ?? 0
+        let r = Double((n >> 16) & 0xFF) / 255
+        let g = Double((n >> 8) & 0xFF) / 255
+        let b = Double(n & 0xFF) / 255
+        self.init(red: r, green: g, blue: b)
+    }
+}